Antiracing control-equipment



Oct. 12, 1954 L. J. HIBBARD AN'IIRACING common-E UIPMENT Filed June 21, 1951 Trpin Line INVENTOR Lloyd J; Hibburd.

ATTORNEY WITNESSES: Awwz Patented Oct. 12, 1954 ANTIRACING CONTROL-EQUIPMENT Lloyd J. Hibbard, Pittsburgh, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application June 21, 1951, Serial No. 232,811

8 Claims.

My invention relates to anti-racing interlocking-means for a control-equipment consisting of a plurality of contactors, which are controlled by a plurality of relays, which are in turn controlled from one or more master controllers. In its broadest aspects, my invention is applicable 'to any control-equipment using relatively small,

fast, light-duty relays, for controlling a plurality of heavy, relatively slow contactors, which have main-circuit contacts which have to be operated in a predetermined order or sequence. My invention has more particular relation to a multiple-unit or multiple-truck train-control for electrically propelled vehicles, in which a bundle or cable of a plurality of control-wires are used, in what is known as a train-line, for carrying the controlling-currents from one cab or car to another, or even from one motor-driven truck to another.

The relays which energize the contactor-controlling coils are known to be subject to occasional troubles or faulty operations, due to jammed contacts or welded contacts, which prevent a relay from opening when it should, or dirty or gritty contacts, which may prevent a relay-contact from closing when it should. This is true, even if the controller and the controllingcircuits for therelays are in perfect operatingorder. For these reasons, it has been the practice, for several decades, to put interlocks on the contactors, which carry the all-important main-circuit contacts. These contactor-interlocks have, under normal circumstances, successfully and adequately controlled the sequence of contactor-operations, in accordance with whatever contact-sequence has been required, in any given case; but this successful operation has not been maintained when there has been contactorracing, that is, when abnormal conditions have arisen, in which there has been a simultaneous energization of the operating-coils of two or more contactors which ought not be closed at the same time.

Under such switch-racing circumstances, all of the simultaneously energized contactors would" faultily closed contactor-contacts may have done great damage to the main power-circuits or apparatus controlled by said contactors, occasionally resulting in the burning out of apparatus or the starting of serious fires, and always resulting in serious burning of the contactor-contacts. This has constituted a serious problem, which has been recognized in the industry, at least since 1936. Prior to my present invention, no practical corrective-means have been conceived, having the necessary simplicity to make them commercially acceptable on the equipments in question.

So far as my broadly conceived invention is concerned, it is immaterial why or how a plurality of contactors, which should have been operated sequentially, were occasionally operated simultaneously. As a matter of interest, however, and for the better understanding of the circumstances with which my invention is associated, it may be mentioned that such faulty simultaneous energizations might result from overlapping master-controller fingers or contacts, due, for example, to stopping the mastercontroller between notches, or from short-circuits or grounds on the train-lines or other control-wires, due to moisture from escaping steam from nearby steam-lines, or the falling of control-covers against terminals, or from improper connections during extensive overhauls when the flag-markings on the wire-terminals have become obliterated,

It is a difficult problem to provide a simple means for causing a large group of electrically controlled main-circuit contact-making devices to operate sequentially, according to a predetermined sequence, when their control-coils are simultaneously electrically energized. As a rule, out-interlocks will have to be provided, in any case, on these main-circuit contact-making devices, for serial inclusion ineither the positive or negative supply-lead which supplies electrical controlling-energy for these main-circuit contact-making devices; and sometimes, when it is necessary to control the retrogression-sequence as well as the progression-sequence, it is necessary to provide a series of out-interlocks in both the negative and the positive supply-leads.

There are certain requirements governing the successful making device on which it is located, that it will deenergize the next contact-making device of the sequence quick enough, in the event that both contact-making devices are simultaneously energized, to prevent said next contact-making device from continuing to close, by its own inertia, on the electrical closing-impulse which was given to it prior to the opening of the out-interlock of the preceding contact-making device of the series. This is called switch-racing.

Of course, if there is enough space available, on which to put all the necessary interlocks or auxiliary switch-contacts which could be desired, it would be possible to prevent this switch-racing by using a large number of in-interlocks on the main-circuit contact-making devices, but these in-interlocks could not be serially included in either the positive or negative supply-lead, which supplies electrical controlling-energy for a series of main-circuit contact-making devices, but these in-interlocks would have to be duplicated in the individual circuits of each one of the control-coils for the contact-making devices which are to be afiected. In small operations, where there are only three or four steps in the sequence, it'might be possible, in some cases, to use this sort of ininterlock sequential control, but even in such small operations, the required number of interlocks and the complexity of th circuit-connections would be quite serious.

In large modern railway-control operations, where there are ten, twenty, or even thirty steps in the required sequential control, there simply is not room to provide the large number of electrical interlocks which would be needed to prevent the possibility of switch-racing, in the event of the simultaneous energization of the control-coils of a plurality of switches or contact-making devices, even though the user of the apparatus could tolerate the maintenance-burden of supervising the large number of interlocks and the complicated wiring-circuits which would ensue.

My present invention is related to a controlequipment in which it is necessary, for reasons other than switch-racing, to provide sequencerelays, or small fast-operating auxiliary relays, for closing the individual control-coil circuits of the several main-circuit contact-making devices. These auxiliary relays are necessary, for example, whenever the electrical energy which is required by the control-coils of the main-circuit switches is larger than can be successfully handled directly by the master-controller, or whenever a reasonably limited (large) number of train-wires have to be used, in multiple-unit control-systems involving two or more master-controllers, only one of which will be in use at any given time. However, these auxiliary relays, by reason of their very lightness and small-energy requirements, are subject to occasional malfunctions, resulting in failure to either open or close their contacts when they should, so that the interlocks still have to be used on the main-circuit switches or contactmakin devices, regardless of the use of auxiliary relays or their control.

My invention solves all of the foregoing difiiculties in a most simple and direct manner. It duplicates, in the relay-circuit control, the outinterlock controls which are used on the maincircuit contactors, or at least the progressionsequence interlocks of said main-switch control. In this way, the relays will race, if they should be simultaneously energized, but even though the relays do race, the improperly closed relays will immediately drop out again, under the control of their out-interlocks, and these relays are so fast in their operations, that the heavy, sluggishlyoperating main switches will not begin to move, or will not make any substantial movement, before the relays have finished their racing, and have finished sorting themselves out, and have settled down, with only the relays closed, which need to be closed, to constitute the first relays of the desired sequence. In this way, the switchracing has been transferred from the main switches, where great harm will be don by the racing, to the auxiliary relays, where noharm is done by the racing, and racing is prevented in the main-switch assembly.

With the foregoing and other objects in view, my invention consists in the circuits, apparatus, combinations, parts, and methods of design and control, as hereinafter described and claimed, and illustrated in the accompanying drawing, in which the single figure is a diagrammatic view of circuits and apparatus of a very much simplified, and somewhat idealized, control-equipment which involves my invention in an illustrative application or form of embodiment of the invention, showing only the smallest number of parts which are necessary to fully illustrate the invention, and omitting the numerous other safeguards and refinements which make up a modern railwaycontrol installation.

The control-equipment which I have illustrated in the drawing is shown applied to a locomotive or other railway-vehicle, which is represented as comprising a pantograph I3 which receives power by making a slidin contact with a single-phase trolley-wire M. The pantograph l'3 energizes a step-down transformer 15 on the locomotive, and this transformer is provided with a multi-tapped secondary-winding [6. In the particular locomotive which is illustrated, my improved controlequipment involves a group of electrically controlled main circuit contact making devices which are actually tap-switches or contactors which are numbered from C1 to C12, for selecting and controlling the secondary taps of the transformer.

In the particular locomotive-installation which is illustrated, the traction-motors are direct-current motors, only one of which is illustrated, having an armature A. This motor is energized from the selected taps of the transformer-secondary 16, through rectifiers I1 and 18, the return-circuit for the motor being completed through a ripple-reducing choke-coil l9, and the midpoint tapconnection X of the transformer-secondary IS. The anode-leads 2| of the rectifiers l! and I8 are shunted by an alternating-current filter 22, as described and claimed in my application Serial No. 120,331, filed October 8, 1949, now Patent No. 2,636,995, April 28, 1953. In series-circuit relation to the anode-leads is a pair of mutually coupled anode-lead reactors 23, as described and claimed in my copending application Serial No. 210,390, filed February 10, 1951, now Patent No. 2,636,997, April 28, 1953. The'motor is shown as comprising, in addition to the armature A, a serially connected interpole-winding 24 and a series main-field winding 25, which is connected through a reverser '26.

This particular type of rectifier-powered locomotive is shown merely as an example of one application of my invention, which is applicable also to other tap-changing controls, and also to main-circuit switches or contactors which are used to control circuits other than transformertaps.

The tap-switches, or contactors C1 "to C12 are provided with contactor-controlling coils 3|,

which may be. either solenoids for magnetically operating the contactors, or, more usually,.valve magnet coils for controlling air-engines (not shown), which constitute the actual motivatingmeans for operating the switches or contactors, as is well known in the art. In any event, these main-switches or contactors C1 to C12 are large heavy-duty devices, which are relatively sluggishly moved. In the drawing, the sluggish response, or delayed action, of the main contactors 'C1 to C12 is diagrammatically indicated by means of a short-circuited coil or slug 32, which is diagrammatically shown as asecond circle surrounding the circle which represents the controlling-coil 3|, and which is intendedto represent any kind of means for producing a relatively slow action, either by reason of the large inertia of heavy parts, or by way of opening a magnet-valve (not shown), for initiating the operation of an air-engine (not shown), all of which takes a certain amount of time.

So far as my present invention is concerned, the essential feature is that there should be a relatively sluggish or delayed response of the main contactors C1 to C12, when their respective operating-coils 3| are electrically energized.

Each of these main-circuit contactors C1 t C12 has a main-circuit make-contact (or contacts) 33 which is closed by the response of that contactor. At least some of these main contactors, for example, the contactors C1 to Ca in the simplified equipment which is illustrated, are provided with positive-circuit out-interlocks 34,

which are auxiliary control-circuit back-contacts of the midtap X. Thus, on one side of the midtap, are the taps T1, T2 and T3, only three taps being shown, for simplicity of illustration, al-

though it will be understood that ordinarily many more taps would be used, on each side of the midpoint X of the transformersecondary l6. On the other side of the midpoint X are corresponding taps, which are designated T1, T2 and T3. Two preventive-coils are used, designated 36 and 36, respectively, one for each side of the mid- -tap X. The midtaps of the preventive-coils 36 and 36' are used, as shown at 31 and 31', to energize the rectifiers l1 and I8.

The terminals 38 and 39 of one preventive-coil, 36, are connected to the first tap T1 through the lain-circuit contacts 33 of the contactors C1 and C3. These same preventive-coil terminals 38 and 39 are connected to the second tap T2, on the same side of the transformer-midtap X, through the main-circuit contacts 33 of the contactors C5 and C7. Inlike manner, the same preventivecoil' terminals 38 and 39 are connected to the tap T3 through the main-circuit contacts 33 of the contactors C9 and C11. The otherpreventive-coil '36 has its terminals 38' and 39 connected, in a similar manner, to the taps T1, T2 and T on the other side of the midtap X, through. the

main-circuit contacts 33 of different pairsofpthe even-numbered contactors C2 to C12.

Each of the contactor-controlling, coils 3|, of the several contactors C1 to C12 is under the control of a corresponding relatively fast, lightduty, auxiliary sequence-relay X1 to X12, as the case may be. These relays X1 to -X12 are shown as each having a contactor-controlling makecontact (or contacts) 43, which is connected in series with the contactor-coil 3| of the correspondingly numbered contactor C1 to C12, as the case may be. These contactor-controlling relaycontacts 43 are closed by a response of the relay which carries the contact. Each of the relays X1 to X12 is provided with a suitable operatingmeans which includes a relay-controlling coil 44. This relay-controlling coil 44 may bring about the operation or the response of the relay either directly or indirectly: usually it will be a directacting operating-coil or solenoid which magnetically actuates the relay. Each of the relaycontrolling coils 44, of the several relays X1 to X12, has a correspondingly numbered ,energizing-circuit lead, numbered 1 to 12, respectively. Each of these relays X1 to X8 is also provided with an out-interlock 45, which is a control-circuit back-contact which is opened by a response of that relay.

The control-equipment includes one or more master-controllers MC, or other controllingmeans which is under the control of the engineman or other attendant in charge of the controlequipment. In order to prevent backstair circuits, the relay-controlling conductors to l2 :are serially connected to undirectionally conducting rectifiers 47, one rectifier for each circuit, these several rectifiers being connected between the relay-energizing circuits to l2, on the one hand, and the controller-energized.circuits to l2, onthe other hand. The controller MC is illustrated as asimple drum-controller, having an off-position, and nine. runhing-positions, numbered 1. to 9; for connecting the desired relay-controlling wires I to I2 to the positive bus in the desired sequential order.

It is to be understood, of course, that the illustrated master-controller MC maybe any kind or type of controller-means which is capable of performing the sequential relay-controlling functions which have just been mentioned, in whatever order or sequential law may be desired,

in any particular case.

I wish it to be also understood that the terms contactors and relays, as. used herein, are intended to include any contact-making devices of the broad descriptions which have been given, regardless of any special restricted uses of these terms which may sometimes be adoptedin the art.

While my invention. is not limited to any one particular application or situation, it was especially designed for, and has been illustrated in connection with, a multiple-unit train-installation, in which the control-energizing conductors l to [2' are connected to correspondingly numbered conductors in a train-line 49, which may be a line running to other cars or locomotive-cabs in the train, or to other motor-operated trucks of a single electrically powered vehicle. As previously explained, such train-lines are subject to short-circuits and grounds, whereby the diiferent line-conductors l to l2. may

become simultaneously energized: also the controller or controllers MC are subject to faulty contact-operations, the terminals of the consperms 7 ductors I to 12' may sometimes be erroneously connected, and one of the relays X1 ttoX12 '1nay sometimes fail to open'or close'one or more of its contacts when the relay should 'operate. It is under such circumstances that my invention finds perhaps its most important application. .It1 is possible, however, for my invention, or someafeatures of it, to be used in a situationin which the relay-energizing conductors I to 12' are. always deliberately energized together, leaving "therelays to sort out the desired sequential operation, or order of operationrin a manneriwhichwfll now be described.

In operation, the controller lMCxisiarranged toprovide for the orderly closure of the relays X1 to X12, and hence themain-circuit contactors or switches C1 to 012,111 whatever sequentialor- 'dermay be required of any particular controlequipment. The same holds .true for the various interlocks 34, 35 and 45.

In the particular control-equipment whichis illustrated, it is desirable'that four. consecutively numbered contactors, of the main. contactors -C1 to C12, shall always be closedat once, 'in any running-position of the apparatus, and never more than four at once; although, .in.lthe'transition-periods, when the contactorsar-e dropped out, one at a time, and anothen'contactor is pulled in, so as still to leave four contactors energized, there is an instantaneous transition-period in which the dropping out of the droppedout contactor pulls in or energizes "the contactor which is to be newly actuatedin thatsstep of the sequential operation.

Thus, in the illustrated apparatus, it is quite essential that no two of the contactor-switches C1 to C12 shall ever be simultaneously closed on the same preventive-coil terminal 38,39,138 or 3 9; it is essential that neither one of the preventive coils 36 or 36 shall ever be impressed with a greater voltage than the voltage between two adjacent taps, such as the taps T1 and T2, the taps T2 and T3, the taps T1 and T2, and the taps T2 and T3; and it is-usually quite desirable that the taps T1, T2 and Ta on one side of the midpoint X shall never get further than one voltage-step away from the corresponding taps T1, T2 and T3 on the other side of the midpoint X. In this way, the equipment prevents the direct short-circuiting of anyportion of the transformer-secondary l6, or the application of excessively high voltages across thewpreventivecoils 36 and 31, which would result in burnouts of these coils, or the production of. excessive even harmonics in the alternating-current trolley-wire M, as a result of excessively unbalanced voltages in the two alternate half-cycles of the rectifier-operation.

I will first describe the control-circuits for the operating-coils 3| of the main-circuit contactors C1 to C12, because these circuits are old, and have been in use for some time prior to my present invention, The positive relay-supply terminal is connected to a positive :relaycircuit terminal 50, which is extended. through the serially connected out-interlocks -34of the contactors C1 to Ca, respectively, to successively energize the conductors 51 to 58. Thelnegative relay-supply terminal is connected (to a negative relay-circuit terminal 60, which is :extended, through the serially connected outinterlocks 35 of the contactors C12 to C5, respectively, to energize the respective circuit-conductors 12 to 65, respectively.

The C1 contactor-c0113] is connected between S the circuits Bland '65,- with the'X1 relay-contact 43 in seriestherewith; the 'C2 coil is connected between the circuits'fi 0 and J56 with .the X2 relaycontact" 43 in seriestherewith; andthe Caand C4 coils are similarly connectedxbetween the circuit '50 and the circuits vii] and 58, respectively, each in: series with the make-contact 43 0f ;its associatedauxiliary relayifi and X4,'respectively.

The contactor-controlling coils of thexnext our contactorsCa to C8,:are connectedrespectively betweenthe successive positive circuits 5! to 5-4, and the successive negative circuits 69 to 12, each in series with the make-contact 43 of its own corresponding auxiliary relay X5 to Xa. Ordinarily, there would be a number of. groups of {our contactors .like'the contactors C5 to Ca, but my drawing has been simplified to show only one.

The contactor-controlling coils of the last four contactors C9 to C12 are connected, on oneside, to the last four positive conductors 55 to v58, respectively: and onithe other side they are all connected to the negative conductor 60, each contactor-coil being in series with the :makecontact 43 of its correspondingly numbered auxiliary relay Xc'GO X12.

The proper-operational sequence, in the progressive order of acceleration control, is maintained by keeping-fourcontactors, and only four contactors, energized at the same time, as called for by the-'master-controller MC. Thus, the first four contactors, C1 to C4, will 'closefirst,: on the first notch of thecontroller-MC. Then the first contactor C1 will be deenergized and the fifth contactor CsWill' be energized, but before the C5 coil can receive current, the C1 ofl-interlock 34.n1ustbe closed; thatis, the first con- .taotor C1 must open. The sequence of operations thereafter continues, each change consisting in dropping out the'lowest numbered of the contactors, and bringing in the next numbered contactor, until finally thee-last four contactors C9 to C12 are energized, corresponding to the highest-voltage secondary-tap connection, and

, :the highest voltage which is-applied to the traction-motor A. These are the interlocking contact-controls which control the progressive-sequence, and they are accomplished through the action of the positive-circuit off-interlocks of the first eight contactors C1 to Ca,- while the voltage-is being progressively increased, in eight successive steps, from its lowest voltage to its highest voltage.

The retrogressive-sequence, which isunder the control of the negative-circuit off-interlocks '35 ofthe contactors C12 to C5, operates as follows. Assume, for example, .that :the four highestnumbered-contactors C2 to C12 are closed,-on controller-position number 9,.and that the controller is notched back one notch, to position number .8. Under these conditions, the highestnumberedpreviouslyeener-gized contactor, 1 which is C12, will first become deenergized, and will drop out, closing its negative-circuitofieinterlocknfi between the circuits 60 and '12, thereby energizing the operating-coil of the next lower-numbered. contactor, whichwould be Cs, and causing this contactor to close, at which time the four closed contactors would be numbered from Ca "to C11. In like manner, the retrogressive sequence will continue, each time first dropping out the highest-numbered contactor which had been closedyand then, by that closure; drawing in the next lower-numbered contactor; and this retrogres'sive operation will continue until the 9 four lowest-numbered contactors C1 to C4 are the only ones energized.

This contactor-controlling circuit-arrangement has the serious disadvantage of switchracing, in the event of a faulty simultaneous electrical energization of a plurality of contactorcontrolling coils which ought not to be simultaneously energized, as previously described.

The control-circuits for the operating coils 44 of the twelve relays X1 to X12 are novel, not only in including the rectifiers 41, but also in including the oil-interlocks 45 of the first eight relays X1 to X8.

The rectifiers 41, in series with the respective relay-energizing conductors I to [2, prevent unwanted and unintended backstair circuits, which usually result from some kind of ground or short-circuit on one or more of the wires of the train-line 49, or from a faulty response, or failure to respond, in ore of the relays corresponding to X1 to X12 in another cab (not shown). Ordinarily, the relay-energizing wires 1 to 12 are the positive relay-terminals, and the circuit is completed, through other conductors, to the negative relaying terminal Under some faulty operating-conditions, however, one or more of the relay-energizing conductors I to IL, or I to 12', may become negative, or more negative than another one of these conductors, so that current may flow to one relay-coil through its positive relay-energizing conductor, come back through the negative terminal of another relay-coil, and flow back through the faultily negatively energized relay-energizing conductor, getting back to the negative relay-terminal somewhere out on a faulty train-line conductor. For example, such a fault might be caused by a sticking relay on another cab, or on another motor-driven railway-truck, it being understood that, in multipleunit operation, the illustrated equipment will be multiplied, with similar equipments located in different cabs or in different trucks, all being connected through the train-line 49. My rectifiers 4'! prevent this kind of back-circuits, and thus are needed in order to complete the sequential-interlock relay-protection which is provided by the off-interlocks 45 of my relays, as will now be described.

The negative end of my relay-controlling circuit is novel in including the off-interlocks 45 of the first eight relays X1 to Xs. The negative relay-supply terminal is connected to a negative relay-circuit terminal Bil, which is extended through the serially connected out-interlocks 45 of the relays X1 to X8, respectively, to successivelyenergize the conductors Bl to 88. The negative terminals of the relay-controlling coils 44 of the first four relays X1 to X4 are connected directly to the negative terminal 80; while the negative terminals of the relay-controlling coils of the remaining relays X5 to X12 are connected to the respective conductors 8| to 88. In this way, the negative-circuit off-interlocks 45 of the first eight relays X1 to X8 perform, for the relays, the same interlocking functions which are performed, for the contactors, by the positivecircuit (or progressive-sequence) off-interlocks 34 of the first eight contactors C1 to C8, the operation of which has been described.

As a result of the interlocking control-circuits which have been described, both the relays X1 to X12, and the contactors C1 to C12 will race, if there should be a simultaneous electrical energization which reaches the operating-coils of relays or contactors which ought not to be closed simultaneously. It has been pointed out that, in the case of the main-circuit contactors C1 to C12, the sequential interlocks cannot be omitted under any circumstances, because the contactorcontrolling relays and/or their controller-means (including the relay-energizing circuits) are susceptible of faulty relay-operations, including responses and/or non-responses which depart from the desired sequence of operations, as well as including the possibility of simultaneous momentary, or even permanent, responses of a plurality of relays which should not simultaneously respond.

By the simple duplication of the progressivesequence interlocks 34 which are provided for the contactors; that is, by adding similar interlocks on the relays, I have not stopped switch-racing (by switch-racing including relay-racing as well as contactor-racing), but I have established a second racing-contest among the fastacting relays, with interlocking-means for making sure that the erroneously closing relays, in this race, will promptly be locked out, and reopen again, ultimately leaving only the closing relay or relays which ought to be closed. It insures that the lowest-numbered relays, of the several relays that may be energized simultaneously, always win the race. And this sortingout process of the relays, resulting from the racing of the relay-contacts, is so quick that the brief moment during which the erroneously closed relay-contacts 43 are closed, before they are reopened again, will be too quick to cause a response of the corresponding sluggishly moving contactors.

Thus, I have not stopped racing, but I have put the racing among the relays X1 to X12, where it does no harm, and in this way, I have completely eliminated any racing among the contactors C1 to C12, where it would do a great deal of harm, as has been above pointed out. And in curing this long-outstanding evil of racing contactors, I have added no apparatus at all (barring the control-circuit backstairs-preventing rectifiers 41), because the relays which were already in use were provided with a number of contacts, enough contacts so that the out-interlocks 45 were readily available at hand, and the introduction of these relay-interlocks 45 into the relay-circuits introduced scarcely no circuitcomplexity at all.

While I have described my invention in an extremely simplified form, and in only one illustrative application or form of embodiment, I wish it to be understood that my invention is susceptible of many variations, including the substitution of various equivalents, the omission or addition of various features or parts or additional safeguards, and other changes which will suggest themselves to the skilled workers of the art, as different situations arise. I desire, there fore, that the appended claims shall be accorded the broadest construction consistent with their language.

I claim as my invention:

1. Control-equipment characterized by: a plurality of contactors which have to be operated in a predetermined sequence of closings and openings, involving making an operation or operations of each of a plurality of said contactors dependent upon a predetermined previous operation or operations of another contactor or contactors, according to a predetermined law of sequences, each of said contactors having an operating means which includes a contactorcontrolling coil whichhas to be electrically energized in order to cause a contactor-operation in one direction, each of. said contactors having a main-circuit contact or contacts which are closed and opened by the operations of that contactor, and each of a plurality of said contactors also having interlocking-means for preventing each of a plurality of said contactors from remaining operated, if a certain other contactor or contactors is operated, in violation of a predetermined prescribed sequence of operations; a plurality of contactor-controlling relays, each of said relays having an operating-means which includes a relay-controlling coil which has to be electrically energized in order to cause a relay-operation in one direction, each of said relays having a contactor-controlling contact or contacts which are closed and opened by the operations of that relay, and each of a plurality of said relays also having interlocking-means for preventing each of a plurality of said relays from remaining operated, if a certain other relay or relays is operated, in violation of a predetermined prescribed sequence of operations; a controllermeans for energizing said relay-controlling coils in a predetermined sequence; said relays and/or controller-means being susceptible of faulty relay-operations, including responses and/ or nonresponses which depart from the desired sequence of operations, and including the possibility of simultaneous momentary initial responses of a plurality of relays which should not simultaneously respond; and contactor-energizing circuitmeans for putting the energization and deepergization of the contactor-controlling coils under the control of the proper contactor-controlling relay-contacts; the rates of response of said relays being so much faster than the rates of response of said contactors, that said contactors will not be caused to even momentarily respond to the faulty operation of a relay or relays which momentarily respond simultaneously with another relay or relays with which the faultily operating relay or relays should not simultaneously respond, said faultily operating relay or relays immediately returning to their non-operated conditions as a result of the relay-interlocking means.

2. Control-equipment characterized by: a plurality of contactors which have to be operated in a predetermined sequence of closings and openings, involving making an operation or operations of each of a plurality of said contactors dependent upon a predetermined previous operation or operations of another contactor or contactors, according to a predetermined law of sequences, each of said contactors having an operating-means which includes a contactorcontrolling coil which has to be electrically energized in order to cause a contactor-operation in one direction, each of said contactors having a main-circuit contact or contacts which are closed and opened by the operations of that contactor, and each of a plurality of said contactors also having an auxiliary control-circuit contact or contacts which are also closed and opened by the operations of that contactor; a plurality of contactor-controlling relays, each of said relays having an operating-means which includes a relay-controlling coil which has to be electrically energized in order to cause a relay-operation in one direction, each of said relays having a contactor-controlling contact or contacts which are closed and opened by the operations of that relay, and each of a plurality of said relays also having an auxiliary control-circuit contactor, contacts which are also closed and openedby the operations of that relay; a controller-means for energizing said relay-controlling coils inra predetermined sequence; said relays and/ or controller-means being susceptible of faulty relayoperations, including responses and/or nonresponses which depart from the desired sequence of operations, and including the possibility of simultaneous momentary initial responses. of a plurality of relays which should not simultaneously respond; contactor-energizing circuitmeans for putting the energization and deenergization of the contactor-controlling coils under the control of the propercontactor-controlling relay-contacts, said contactor-energizing circuitmeans also including interlocking circuit-means for putting the operations of each of a plurality of said contactors under the control of the proper auxiliary contact or contacts of another contactor or contactors in such manner as to maintain said predetermined sequence of contactor-operations so long as the corresponding relays do not have a faulty relay-operation involving the simultaneous initial responses of a plurality of relays which should not simultaneously respond; and relay-interlocking circuitmeans for putting the relay-operations under the control of the proper auxiliary contact or contacts of other relays in such manner that, in the event of a simultaneous faulty response of'a plurality of relays which should not simultaneously initially respond, the coils of the faultily responding relay 0r relays will be quickly deenergized by the relay-interlocking circuitmeans; the rates of response of said relays being so much faster than the rates of response of said contactors, that said contactors will not be caused to even momentarily respond to the faulty operation of a relay or relays which are quickly deenergized by said relay-interlocking circuit-means.

3. Control-equipment characterized by: a plurality of contactors which have to be operated in a predetermined sequence of closings and openings, involving making an operation or operations of each of a plurality of said contactors dependent upon a predetermined previous operation or operations of another contactor or contactors, according to a predetermined law of sequences, each of said contactors having an operating-means which includes a contactorcontrolling coil which has to be electrically energized in order to cause a contactor-operation in one direction, each of said contactors having a main-circuit contact or contacts which are closed and opened by the operations of that contactor, and each of a plurality of said contactors also having interlocking-means for preventing each of a plurality of said contactors from remaining operated, if a certain other contactor or contactors is operated, in violation of a predetermined prescribed sequence of operations; a plurality of contactor-controlling relays, each of said relays having an operating-means which includes a relay-controlling coil which has to be electrically energized in order to cause a relayoperation in one direction, each of said relays having a contactor-controlling contact or contacts which are closed and opened by the operations of that relay, and a plurality of said relays having relay-interlocking meansfor providing for a predetermined sequence of relay-operations; a controller-means for energizing said relay-controlling coils in a predetermined sequence, said controller-means being subject to short-circuit conditions which tend to simultaneously energize a plurality of relays which should not simultaneously respond; and contactor-energizing circuit-means for putting the energization and deenergization of the contactorcontrolling coils under the control of the proper contactor-controlling relay-contacts; the rates of response of said relays being considerably faster than the rates of response of said contactors.

4. Control-equipment characterized by: a plurality of contactors which have to be operated in a predetermined sequence of closings and openings, involving making an operation or operations of each of a plurality of said contactors dependent upon a predetermined previous operation or operations of another contactor or contactors, according to a predetermined law of sequences, each of said contactors having an operatingmeans which includes a contactor-controlling coil which has to be electrically energized in order to cause the contactor to respond by moving from its non-responsive condition to its responsive condition, each of said contactors having a main-circuit make-contact or contacts which are closed by the response of that contactor, and each of a plurality of said contactors also having an auxiliary control-circuit backcontact or contacts which are opened by a response of that contactor; a plurality of contactor-controlling relays, each of said relays having an operating-means Which includes a relay-controlling coil which has to be electrically energized in order to cause the relay to respond by moving from its non-responsive condition to its responsive condition, each of said relays having a contactor-controlling make-contact or contacts which are closed by the response of that relay, each of a plurality of said relays also having an auxiliary control-circuit backcontact or contacts which are opened by a response of that relay, and the several relaycontrolling coils having coil-leads which are subject to short-circuit conditions wherein supposedly insulated leads are faultily connected together; contactor-energizing circuit-means for energizing the respective contactor-controlling coils, the energizing-circuit of each of said contactor-controlling coils serially including a contactor-controlling make-contact or contacts of a relay or relays, and the energizing-circuit of each of a plurality of said contactor-controlling coils serially including also a control-circuit back-contact or contacts of another contactor or contactors in accordance with a predetermined law of contactor-sequences; controller-means having a plurality of contact-members; relayenergizing circuit-means for energizing the respective leads of the relay-controlling coils, the energizing-circuit for each relay serially including a contact-member of said controller-means, the energizing-circuit for each of a plurality of said relays serially including also a controlcircuit back-contact or contacts of another relay or relays in accordance with a predetermined law of relay-sequences; the rates of responses of said relays being considerably faster than the rates of response or" said contactors.

5. The invention as defined in claim 4, characterized by the relay-energizing circuit-means including a source of direct-current energy for energizing the relay-controlling coils, in combination with a unidirectionally conducting rectifying-means in series circuit relation to each of a plurality of said relay-controlling coils.

6. The invention as defined in claim 4, characterized by said controller-means being subject to faulty operating-conditions wherein supposedly separately controlled contact-members are erroneously simultaneously closed.

7. The invention as defined in claim 6, characterized by the relay-energizing circuit-means including a source of direct-current energy for energizing the relay-controlling coils, in combination with a unidirectionally conducting rectifying-means in series circuit relation to each relay-controlling coil.

8. Control-equipment for causing a group of electrically controlled main-circuit contact-making devices to operate sequentially, according to a predetermined sequence, comprising the combination, with said main-circuit contact-making devices, of a group of electrically controlled auxiliary-circuit contact-making devices for electrically controlling said main-circuit contactmaking devices, at least some of the contactmaking devices of each group having interlockproviding auxiliary contacts, and interlocking circuits for each group, using the interlocks of that group in such fashion as to maintain a desired predetermined sequence if the initially operable main-circuit or auxiliary-circuit contact-making device is properly selected, as the case may be, but causing a race between the contact-making devices of that group, in the event of the simultaneous initial energization of devices which ought not operate simultaneously, in that group; the auxiliary-circuit contactmaking devices being so much faster than the main-circuit contact-making devices that, in the event of a race of the auxiliary-circuit contactmaking devices, the race will be over, and the erroneously responding auxiliary-circuit contactmaking devices will have been restored, by their interlocks, to a non-responsive condition, before the undesired main-circuit contact-making devices will have received a response-producing amount of energization.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,254,724 Bany Sept. 2, 1941 2,339,976 Brown Jan. 25, 1944 2,498,249 Cook Feb. 21, 1950 2,563,824 Dunlap Aug. 14, 1951 2,616,958 Westerveld Nov. 4, 1952 

